Compilare: user.cpp: In function ‘void dfs_st(int, int)’: user.cpp:33:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < arb[nod].v.size(); ++ i){ ^ user.cpp: In function ‘int main()’: user.cpp:211:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < op.size(); ++ i){ ^